From: Jeff Garzik <jeff@garzik.org>
To: Michael Chan <mchan@broadcom.com>
Cc: davem@davemloft.net, netdev@vger.kernel.org
Subject: Re: [PATCH 10/11][TG3]: Reduce spurious interrupts.
Date: Fri, 04 May 2007 20:42:43 -0400 [thread overview]
Message-ID: <463BD303.7000500@garzik.org> (raw)
In-Reply-To: <1178326521.4859.26.camel@dell>
Michael Chan wrote:
> [TG3]: Reduce spurious interrupts.
>
> Spurious interrupts are often encountered especially on systems
> using the 8259 PIC mode. This is because the I/O write to deassert
> the interrupt is posted and won't get to the chip immediately. As
> a result, the IRQ may remain asserted after the IRQ handler exits,
> causing spurious interrupts.
>
> An unconditional read to flush the I/O write to force the IRQ to de-
> assert immediately is not desirable because it impacts performance in
> the fast path. So we only do this after we have some indications of
> spurious interrupts.
>
> Signed-off-by: Michael Chan <mchan@broadcom.com>
hmmmm, this is a bit questionable that it needs to be here.
I think it's just a fact of life that it is important to flush certain
writes...
I'm not sure a driver needs to be adding code to avoid the obvious
solution. It would be annoying if all drivers had code to do this.
Jeff
next prev parent reply other threads:[~2007-05-05 0:42 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-05-05 0:55 [PATCH 10/11][TG3]: Reduce spurious interrupts Michael Chan
2007-05-05 0:42 ` Jeff Garzik [this message]
2007-05-05 1:45 ` Michael Chan
2007-05-05 2:42 ` David Miller
2007-05-05 2:50 ` Michael Chan
2007-05-05 3:47 ` David Miller
2007-05-06 0:15 ` Michael Chan
2007-05-06 0:19 ` [PATCH revised 10/11][TG3]: Eliminate " Michael Chan
2007-05-07 7:26 ` David Miller
2007-05-06 0:21 ` [PATCH revised 11/11][TG3]: Update version and reldate Michael Chan
2007-05-07 7:26 ` David Miller
2007-05-07 16:39 ` [PATCH 10/11][TG3]: Reduce spurious interrupts Rick Jones
[not found] ` <1178562469.4859.70.camel@dell>
2007-05-07 17:44 ` Rick Jones
2007-05-07 18:41 ` Michael Chan
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